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Diffstat (limited to 'lib/VMCore/DominatorInternals.cpp')
-rw-r--r-- | lib/VMCore/DominatorInternals.cpp | 140 |
1 files changed, 0 insertions, 140 deletions
diff --git a/lib/VMCore/DominatorInternals.cpp b/lib/VMCore/DominatorInternals.cpp deleted file mode 100644 index abb87cd381..0000000000 --- a/lib/VMCore/DominatorInternals.cpp +++ /dev/null @@ -1,140 +0,0 @@ -//==- DominatorInternals.cpp - Dominator Calculation -------------*- C++ -*-==// -// -// The LLVM Compiler Infrastructure -// -// This file was developed by Owen Anderson and is distributed under -// the University of Illinois Open Source License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// - -#include "llvm/Analysis/Dominators.h" -#include "llvm/ADT/DenseMap.h" -#include "llvm/ADT/SmallPtrSet.h" -//===----------------------------------------------------------------------===// -// -// DominatorTree construction - This pass constructs immediate dominator -// information for a flow-graph based on the algorithm described in this -// document: -// -// A Fast Algorithm for Finding Dominators in a Flowgraph -// T. Lengauer & R. Tarjan, ACM TOPLAS July 1979, pgs 121-141. -// -// This implements both the O(n*ack(n)) and the O(n*log(n)) versions of EVAL and -// LINK, but it turns out that the theoretically slower O(n*log(n)) -// implementation is actually faster than the "efficient" algorithm (even for -// large CFGs) because the constant overheads are substantially smaller. The -// lower-complexity version can be enabled with the following #define: -// -#define BALANCE_IDOM_TREE 0 -// -//===----------------------------------------------------------------------===// - -namespace llvm { - -void Compress(DominatorTreeBase& DT, BasicBlock *VIn) { - - std::vector<BasicBlock *> Work; - SmallPtrSet<BasicBlock *, 32> Visited; - BasicBlock *VInAncestor = DT.Info[VIn].Ancestor; - DominatorTreeBase::InfoRec &VInVAInfo = DT.Info[VInAncestor]; - - if (VInVAInfo.Ancestor != 0) - Work.push_back(VIn); - - while (!Work.empty()) { - BasicBlock *V = Work.back(); - DominatorTree::InfoRec &VInfo = DT.Info[V]; - BasicBlock *VAncestor = VInfo.Ancestor; - DominatorTreeBase::InfoRec &VAInfo = DT.Info[VAncestor]; - - // Process Ancestor first - if (Visited.insert(VAncestor) && - VAInfo.Ancestor != 0) { - Work.push_back(VAncestor); - continue; - } - Work.pop_back(); - - // Update VInfo based on Ancestor info - if (VAInfo.Ancestor == 0) - continue; - BasicBlock *VAncestorLabel = VAInfo.Label; - BasicBlock *VLabel = VInfo.Label; - if (DT.Info[VAncestorLabel].Semi < DT.Info[VLabel].Semi) - VInfo.Label = VAncestorLabel; - VInfo.Ancestor = VAInfo.Ancestor; - } -} - -BasicBlock *Eval(DominatorTreeBase& DT, BasicBlock *V) { - DominatorTreeBase::InfoRec &VInfo = DT.Info[V]; -#if !BALANCE_IDOM_TREE - // Higher-complexity but faster implementation - if (VInfo.Ancestor == 0) - return V; - Compress(DT, V); - return VInfo.Label; -#else - // Lower-complexity but slower implementation - if (VInfo.Ancestor == 0) - return VInfo.Label; - Compress(DT, V); - BasicBlock *VLabel = VInfo.Label; - - BasicBlock *VAncestorLabel = DT.Info[VInfo.Ancestor].Label; - if (DT.Info[VAncestorLabel].Semi >= DT.Info[VLabel].Semi) - return VLabel; - else - return VAncestorLabel; -#endif -} - -void Link(DominatorTreeBase& DT, BasicBlock *V, BasicBlock *W, - DominatorTreeBase::InfoRec &WInfo) { -#if !BALANCE_IDOM_TREE - // Higher-complexity but faster implementation - WInfo.Ancestor = V; -#else - // Lower-complexity but slower implementation - BasicBlock *WLabel = WInfo.Label; - unsigned WLabelSemi = DT.Info[WLabel].Semi; - BasicBlock *S = W; - InfoRec *SInfo = &DT.Info[S]; - - BasicBlock *SChild = SInfo->Child; - InfoRec *SChildInfo = &DT.Info[SChild]; - - while (WLabelSemi < DT.Info[SChildInfo->Label].Semi) { - BasicBlock *SChildChild = SChildInfo->Child; - if (SInfo->Size+DT.Info[SChildChild].Size >= 2*SChildInfo->Size) { - SChildInfo->Ancestor = S; - SInfo->Child = SChild = SChildChild; - SChildInfo = &DT.Info[SChild]; - } else { - SChildInfo->Size = SInfo->Size; - S = SInfo->Ancestor = SChild; - SInfo = SChildInfo; - SChild = SChildChild; - SChildInfo = &DT.Info[SChild]; - } - } - - DominatorTreeBase::InfoRec &VInfo = DT.Info[V]; - SInfo->Label = WLabel; - - assert(V != W && "The optimization here will not work in this case!"); - unsigned WSize = WInfo.Size; - unsigned VSize = (VInfo.Size += WSize); - - if (VSize < 2*WSize) - std::swap(S, VInfo.Child); - - while (S) { - SInfo = &DT.Info[S]; - SInfo->Ancestor = V; - S = SInfo->Child; - } -#endif -} - -} |